The present invention relates to an apparatus for transporting particulate material and, more particularly, to material transfer systems for transferring particulate material from a first fluidized bed to a second fluidized bed.
Material transfer systems adapted to transfer particulate material typically include a hollow duct and means to cause a high velocity flow of gas, known as activating gas, in the duct. Particulate material is introduced into the duct at an entry point, entrained in the activating gas, and thereby transported along the duct to a discharge point. In general, this type of structure can efficiently and conveniently transport large quantities of particulate material.
Special problems arise when conventional material transfer systems are utilized to transfer particulate material between fluidized beds. As is well known, fluidized beds employ a vertical rising stream of gas moving upwardly at a velocity sufficient to overcome the force of gravity to suspend or fluidize small particles. The overall size of the fluidized bed is controlled, in part, by accurately controlling the amount of fluidized particulate material. Conventional material transfer systems which utilize high pressure activating gas can cause disturbances in the fluidizing gas stream which adversely effect the operation of the fluidized bed. Likewise, conventional material transfer systems generally cannot transport particulate material in accurately controlled amounts to permit convenient control of the size of the fluidized bed.